This is a reland of 16cbfb41df
Tests now rely on `shaderDerivativeSupport` and `integerSupport` as
proxies to indicate ES3 support. The SwitchStatement test has been
adjusted to hopefully confuse fewer compilers.
Original change's description:
> Implement statements and expressions in DSL C++ code generator.
>
> This CL removes the bulk of the existing C++ code generator, especially
> all the complex format-string assembly code. It has been replaced with
> actual DSL code generation. Simple IR can now be successfully translated
> to a working DSL fragment processor.
>
> This CL also adds a simple test harness which is patterned after the
> existing SkSLTest; it renders a pixel, reads it back, and fails the test
> if the result isn't solid green (RGBA=0101).
>
> This CL doesn't implement every feature. Some obvious gaps include:
> - Sampling from children
> - Uniforms/inputs of any kind
> - Function calls of any kind
>
> Change-Id: Ib80c23fe1ba4453f7c3cb43b65f93c5ea0deb709
> Bug: skia:11854
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/396757
> Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: John Stiles <johnstiles@google.com>
Bug: skia:11854, skia:11891
Change-Id: I91363e31f34611d15ae350b52d6fc459feeace9c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/399076
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
c412688798